1. Field of the Invention
The present invention relates to lasers and particularly to the efficient generation of laser radiation by the frequency conversion of the output of an injection-locked diode laser structure which has a large active area.
2. Description of the Prior Art
The direct frequency doubling of a diode laser output promises to be the most efficient method of generating coherent blue emission (in the exemplary 390 to 440 nm spectral range). Unfortunately, second-harmonic generation (SHG) efficiency, using diode lasers, has been limited in the past by their relatively low available power output. The highest SHG powers obtained with a diode laser source and a single pass optical configuration, using a potassium niobate (KNbO.sub.3) crystal as a frequency doubler, were 0.28 micro watts for continuous wave (CW) operation and 0.35 milliwatts for pulsed operation, as disclosed in the published article of J.-C. Baumert et al., "High Efficiency Second-Harmonic Generation In KNbO.sub.3 Crystals", Optics Communications, Vol. 48, No. 3, pp. 215-220 (Dec. 1, 1983).